This invention relates to a novel emulsifier composition which exerts excellent improvement effects to starch containing food.
Due to its function and safety, mono- and diglyceride is widely used as emulsifier in the present food processing industry, and this function differs depending on the purity, appearance, physical and chemical properties, and the types of fatty acid that constitute the emulsifier.
In the case of starch containing food, such emulsifiers are required to react well, particularly with starch, to obtain a complex with the starch. Saturated fatty acid monoglyceride having 14 to 18 carbon atoms and of a high purity distilled monoglyceride is known to meet this requirement.
In the case of using mono- and diglyceride in the fat phase, there is no restriction on the physical properties of the mono- and diglyceride because they can be dissolved into fat. However, in case of starch-containing food, it is desirable to use mono- and diglyceride in the aqueous phase in order to obtain a starch-complexing improvement effect.
In these circumstances or where the emulsifier is mixed with the raw material in powdered form, physical appearance, physical and chemical properties and surface condition have a significant bearing on this function.
Monoglyceride is known to be polymorphic and is classified according to sub-.alpha., .alpha., .beta.' and .beta.-crystalline forms which are arranged in order of increasing melting points. The .beta.-crystalline form is the most stable thermodynamically and monoglyceride has always been marketed in the .beta.-crystalline form.
The reason why the .alpha.-crystalline form is more effective in the aqueous phase can be assumed to be because of a different in hydrophilicity. As a means of obtaining the .alpha.-crystalline form, there is a so-called conjoined crystal method employing the combined use of saturated fatty acid monoglyceride and fatty acid propylene-glycol ester (J. Am. Oil., Chem. 40,725, (1963)); or a method wherein a dispersion in water is formed at a temperature below the melting point of monoglyceride. However, each of these methods have disadvantages, such as a small content of monoglyceride, difficulty in temperature control or in preservation properties.
From these standpoints, it would be advantageous to obtain a monoglyceride having the stable .beta.-crystalline form while, at the same time, exhibiting good functional properties. Various methods have been considered as means for improving the hydrophilic properties. In other to increase the surface area of crystals, there is a method whereby minute crystals were obtained by re-crystallization using a solvent (Patent: TOKU-KOSHO No. 50-34613) and a method whereby an aqueous dispersion of the .beta.-crystalline form was obtained by adding a stabilizer into a dispersion or a method whereby a dry powered monoglyceride was obtained by adding binders into a dispersion (Patent TOKU-KOSHO No. 44-26900).
Each of these methods have excellent improvement effects. However, with respect to obtaining powdered monoglyceride, the methods were disadvantageous because they tended to be expensive from the stand-point of production efficiency, and a product in paste form proved to be inferior in handling, preservation and stability. Therefore, the development of a more simplified process has long been desired for obtaining a powdered monoglyceride which is effective in the aqueous phase. As a result of intensive research work in consideration of these shortcomings, the present inventors discovered a novel emulsifier composition which provides good quality improvement effects to starch containing food, and which is easier to handle, less expensive, withstands longer preservation time and is stable.